U.S. President Donald Trump speaks while introducing Kirstjen Nielsen, U.S. secretary of Homeland Security nominee, at the White House in Washington, D.C., U.S., on Thursday, Oct. 12, 2017. Trump announced his nomination of Kirstjen...More

U.S. President Donald Trump speaks while introducing Kirstjen Nielsen, U.S....U.S. President Donald Trump speaks while introducing Kirstjen Nielsen, U.S. secretary of Homeland Security nominee, at the White House in Washington, D.C., U.S., on Thursday, Oct. 12, 2017. Trump announced his nomination of Kirstjen Nielsen, a top aide to White House Chief of Staff John Kelly, to succeed him as secretary of Homeland Security. Photographer: T.J. Kirkpatrick/Bloomberg via Getty ImagesLessMore

Kirstjen Nielsen, U.S. secretary of Homeland Security nominee, speaks after an introduction from U.S. President Donald Trump at the White House in Washington, D.C., U.S., on Thursday, Oct. 12, 2017. Trump announced his nomination of...More

Kirstjen Nielsen, U.S. secretary of Homeland Security nominee, speaks after an...Kirstjen Nielsen, U.S. secretary of Homeland Security nominee, speaks after an introduction from U.S. President Donald Trump at the White House in Washington, D.C., U.S., on Thursday, Oct. 12, 2017. Trump announced his nomination of Kirstjen Nielsen, a top aide to White House Chief of Staff John Kelly, to succeed him as secretary of Homeland Security. Photographer: T.J. Kirkpatrick/Bloomberg via Getty ImagesLessMore

Kirstjen Nielsen, U.S. secretary of Homeland Security nominee, speaks after an introduction from U.S. President Donald Trump, not pictured, at the White House in Washington, D.C., U.S., on Thursday, Oct. 12, 2017. Trump announced his...More

Kirstjen Nielsen, U.S. secretary of Homeland Security nominee, speaks after an...Kirstjen Nielsen, U.S. secretary of Homeland Security nominee, speaks after an introduction from U.S. President Donald Trump, not pictured, at the White House in Washington, D.C., U.S., on Thursday, Oct. 12, 2017. Trump announced his nomination of Kirstjen Nielsen, a top aide to White House Chief of Staff John Kelly, to succeed him as secretary of Homeland Security. Photographer: T.J. Kirkpatrick/Bloomberg via Getty ImagesLessMore

U.S. President Donald Trump speaks while introducing Kirstjen Nielsen, U.S. secretary of Homeland Security nominee, at the White House in Washington, D.C., U.S., on Thursday, Oct. 12, 2017. Trump announced his nomination of Kirstjen...More

U.S. President Donald Trump speaks while introducing Kirstjen Nielsen, U.S....U.S. President Donald Trump speaks while introducing Kirstjen Nielsen, U.S. secretary of Homeland Security nominee, at the White House in Washington, D.C., U.S., on Thursday, Oct. 12, 2017. Trump announced his nomination of Kirstjen Nielsen, a top aide to White House Chief of Staff John Kelly, to succeed him as secretary of Homeland Security. Photographer: T.J. Kirkpatrick/Bloomberg via Getty ImagesLessMore

Elaine Chao, U.S. transportation secretary, arrives before U.S. President Donald Trump, not pictured, introduces Kirstjen Nielsen, U.S. secretary of Homeland Security nominee, not pictured, during an event at the White House in...More

Elaine Chao, U.S. transportation secretary, arrives before U.S. President Donald...Elaine Chao, U.S. transportation secretary, arrives before U.S. President Donald Trump, not pictured, introduces Kirstjen Nielsen, U.S. secretary of Homeland Security nominee, not pictured, during an event at the White House in Washington, D.C., U.S., on Thursday, Oct. 12, 2017. Trump announced his nomination of Nielsen, a top aide to White House Chief of Staff John Kelly, to succeed him as secretary of Homeland Security. Photographer: T.J. Kirkpatrick/Bloomberg via Getty ImagesLessMore

Kirstjen Nielsen, U.S. secretary of Homeland Security nominee, listens to an introduction from U.S. President Donald Trump at the White House in Washington, D.C., U.S., on Thursday, Oct. 12, 2017. Trump announced his nomination of...More

Kirstjen Nielsen, U.S. secretary of Homeland Security nominee, listens to an...Kirstjen Nielsen, U.S. secretary of Homeland Security nominee, listens to an introduction from U.S. President Donald Trump at the White House in Washington, D.C., U.S., on Thursday, Oct. 12, 2017. Trump announced his nomination of Nielsen, a top aide to White House Chief of Staff John Kelly, to succeed him as secretary of Homeland Security. Photographer: T.J. Kirkpatrick/Bloomberg via Getty ImagesLessMore

U.S. First Lady Melania Trump arrives before U.S. President Donald Trump, not pictured, introduces Kirstjen Nielsen, U.S. secretary of Homeland Security nominee, not pictured, during an event at the White House in Washington, D.C.,...More

U.S. First Lady Melania Trump arrives before U.S. President Donald Trump, not...U.S. First Lady Melania Trump arrives before U.S. President Donald Trump, not pictured, introduces Kirstjen Nielsen, U.S. secretary of Homeland Security nominee, not pictured, during an event at the White House in Washington, D.C., U.S., on Thursday, Oct. 12, 2017. Trump announced his nomination of Nielsen, a top aide to White House Chief of Staff John Kelly, to succeed him as secretary of Homeland Security. Photographer: T.J. Kirkpatrick/Bloomberg via Getty ImagesLessMore

Rex Tillerson, U.S. secretary of State, arrives before U.S. President Donald Trump, not pictured, introduces Kirstjen Nielsen, U.S. secretary of Homeland Security nominee, not pictured, during an event at the White House in Washington,...More

Rex Tillerson, U.S. secretary of State, arrives before U.S. President Donald Trump,...Rex Tillerson, U.S. secretary of State, arrives before U.S. President Donald Trump, not pictured, introduces Kirstjen Nielsen, U.S. secretary of Homeland Security nominee, not pictured, during an event at the White House in Washington, D.C., U.S., on Thursday, Oct. 12, 2017. Trump announced his nomination of Nielsen, a top aide to White House Chief of Staff John Kelly, to succeed him as secretary of Homeland Security. Photographer: T.J. Kirkpatrick/Bloomberg via Getty ImagesLessMore

Wilbur Ross, U.S. commerce secretary, from left, Rick Perry, U.S. secretary of energy, and Ben Carson, secretary of Housing and Urban Development (HUD), speak while arriving before U.S. President Donald Trump, not pictured, introduces...More

Wilbur Ross, U.S. commerce secretary, from left, Rick Perry, U.S. secretary of...Wilbur Ross, U.S. commerce secretary, from left, Rick Perry, U.S. secretary of energy, and Ben Carson, secretary of Housing and Urban Development (HUD), speak while arriving before U.S. President Donald Trump, not pictured, introduces Kirstjen Nielsen, U.S. secretary of Homeland Security nominee, not pictured, during an event at the White House in Washington, D.C., U.S., on Thursday, Oct. 12, 2017. Trump announced his nomination of Nielsen, a top aide to White House Chief of Staff John Kelly, to succeed him as secretary of Homeland Security. Photographer: T.J. Kirkpatrick/Bloomberg via Getty ImagesLessMore

Kirstjen Nielsen, U.S. secretary of Homeland Security nominee, smiles after an introduction from U.S. President Donald Trump at the White House in Washington, D.C., U.S., on Thursday, Oct. 12, 2017. Trump announced his nomination of...More

Kirstjen Nielsen, U.S. secretary of Homeland Security nominee, smiles after an...Kirstjen Nielsen, U.S. secretary of Homeland Security nominee, smiles after an introduction from U.S. President Donald Trump at the White House in Washington, D.C., U.S., on Thursday, Oct. 12, 2017. Trump announced his nomination of Kirstjen Nielsen, a top aide to White House Chief of Staff John Kelly, to succeed him as secretary of Homeland Security. Photographer: T.J. Kirkpatrick/Bloomberg via Getty ImagesLessMore